They illustrate the covers of books on the Middle Ages and the Renaissance, they are essential props for essays on the ‘Golden Age of Islamic Science’, they can even be found in some of the most well-known Hollywood blockbusters. But what are astrolabes exactly? Who makes and uses them? And most importantly, maybe, what are they used for?

Invented by the ancient Greeks, developed by mathematicians and astronomers in all parts the Islamic World, used by medieval Jewish scholars and – together with the ‘Arabic’ numerals - introduced into the Christian World, the astrolabe truly is a mirror of cross-cultural inspiration. Timekeeping, direction-finding, casting of horoscopes, solving of trigonometric functions, surveying of land – all of these challenges can be solved with this one instrument. And even if none of these appeal to the user, astrolabes are amongst the most stunning artifacts produced out of metal – a joy to behold for any museum visitor.

This lecture, which is based on twenty years research by the speaker, puts one of the most enigmatic, sophisticated and versatile scientific instrument of all times into its cultural and social context(s).